Vacuum-lamp.



No. 785,157. PATENTED MAR. 21, 1905.

v J. M. DAVEY.

VACUUM LAMP.

APPLICATION FILED JUNE 27. 1903.

' the tubes. between Patented March 21, 1905.

JOSEPH M. DAVEY, OF ST. LOUIS, MlSSGUlti.

VACUUM-LAMP.

SPECIFICATIOK forming part of Letters Patent No. 785,157, dated March21, 1905.

Application filed June 27, 1903. Serial No. 163,377.

To It whom, it may con/corn:

Be it known thatI, JOSEPH M. DAVEY, a citizen of the United States,residingat St. Louis, Missouri, have invented a certain new and usefulImprovement in Vacuum-Lamps, of which the following is a full, clear,and exact description, such as will enable others skilled in the art towhich it appertains to make and use the same, reference being had to theaccompanying drawings, forming part of this specification, in whichFigure 1 is a sectional view of the completed lamp. Fig. 2 is asectional view of which the leading-in wires are located, the inner tubebeing shown separated from the outer tube by full lines and being shownin its service position with relation to said outer tube by dottedlines.

Fig. 3 is a sectional view showing the said tubes in their serviceposition and also showing the leading-in wires and the filamentconnected to the same. Fig. 4 is a view showing the said tubes connectedto the bulb before the bulb has been evacuated, and Fig. 5 is a viewgenerall similar to Fig. 4 and showing the device after the bulb hasbeen evacuated and the inner tube has been closed This invention relatesto improvements in vacuum-lam s, such as the well-known incandescent eectric lamps, and more particularly that type of lamp wherein theformation of a teat incident to the sealing of an evacuating-o ening isobviated.

To this en. and also to improve generally upon devices of the-characterindicated, the invention consists in the various matters hereinafterdescribed and claimed.

Referring now more particularly to the drawings, 1 indicates a bulbsimilar to those employed in the construction of incandescent electriclamps, wherein no opening is left in the bottom of the same for thepurpose of evacuating it. An outer tube 2 lies within said bulb and hasits outer or up or end flared 0r flanged, as shown at 3, sai flaredportion being of slightly larger diameter than the interior diameter ofthe neck, so that when said' 'tube is in osition the flared portionrests upon the e ge of the neck 4 of the bulb, said flared portion ofthe outer tube being thus supported while it is being fused to sald neckof the bulb. Within said outer tube is an inner tube 5, whose exteriordiame ter is less than the interior diameter of the outer tube and whoselower or inner end is flared, as shown at 6, said flared portion beingof slightly larger diameter than. the interior diameter of the tube 5for the purpose of resting against the lower or inner edge of the outertube and being fused thereto. The usual leading-in wires 7 extend in thespace between the said tubes and project inwardly beyond the tubes inorder to permit the customary attachment of the carbon or other filament8.

In assembling the present lamp the tubes 2 and 5 are placed in thepositions in which they are shown by full lines in Fig. 2, and theleading-in wires 7 are threaded through the space between said tubes,after which the tubes are brought together, as shown in Fig. 3, and theflared portion 6 of the inner tube is fused to the outer tube. Thecarbon filament 8 is then attached to ner ends of the leading-in wires.After this has been done the connected tubes, with their carriedleading-in wires and filament, are then inserted in the bulb 1 throughthe open neck 4 of the latter, as shown in Fig. 4, and the flaredportion 3 of the outer tube is fused to the edge of said neck. The bulbis then evacuated through theinner tube 5, and'after this has'been donethe outer end of said inner tube is closed by fusing or otherwise, asshown in Fig. 5. The usual porcelain cap 9 and the customarycontact-pieces 10'and 11 can then be placed upon the bulb in thecustomary manner. I

A lamp constructed in accordance with the present invention entirelyobviates the teat upon the bulb and provides forconveniently evacuatingsaid bulb, the various )arts of the lamp being conveniently arrange andeasily connected together. Furthermore, the

fused end of the evacuatingtube 5 is protect ed by the porcelain cap 9.

I am aware that minor changes in the construction, arrangement, andcombination of the projecting indescribed without in the least departingfrom the nature and principle of my lnvention.

Having thus described the invention,what

is claimed as new, and desired to be secured 5 by Letters Patent, is

In a vacuum-lamp, the combination with a bulbhaving a neck portion, of atube 2 of smaller diameter thanvsaid neck extending into said bulb andhaving its outer end flared to outwardly as at 3, said flaredportionbeing of larger diameter than the interior diameter of the neck andconnected at its edge to the outer end of said neck, the inner or lowerend of said tube being substantially flat, an inner I5 tube 5 vofsmaller diameter than the tube 2 I and of greater length, said innertube 5 hav-

